My check engine light is on. Got two codes: P0171 & P0442. What do they mean and cost to repair?

P0171 probably means an air intake leak. Usual culprits are the PCV hose or the intake gaskets. Need to inspect to find out. P0442 could be a loose or improper sealing gas cap or a small leak in the EVAP recovery system. For prices, try the estimator at the top of the page or call a shop in your area.